Color reproduction is one of the various characteristics which are required of silver halide color photographic light-sensitive materials (referred to hereinafter simply as light-sensitive materials).
The use of colored couplers in color negative photographing materials, for example, for correcting the unwanted absorptions of the colored images, is one means of improving color reproduction. Disclosures concerning these colored couplers have been made in many publications and patents, and as one example reference can be to the disclosures made in Research Disclosure, No. 17643, section VII-G.
So-called magenta colored cyan couplers which have a peak absorption wavelength in the visible region in the range from about 500 to 600 nm, and which undergo a coupling reaction with the oxidized product of a primary aromatic amine developing agent and form cyan images which have an absorption peak wavelength of about 630-750 nm are used at the present time in order to correct the unwanted absorptions of the cyan image using colored couplers.
However, the visible region absorbance of the cyan image also has an absorbance in the region of 400-500 nm. If these unwanted absorptions are corrected by means of a so-called yellow colored coupler, an effect resembling photographically the inter-layer effect can be obtained in the yellow colored image layer from the cyan colored image and it can be anticipated that this will be desirable from the viewpoint of color reproduction, and this possibility has been disclosed, for example, in JP-A-61-221748 and JP-A-1-319744. (The term "JP-A" as used herein signifies an "unexamined published Japanese patent application".)
However, the conventional yellow colored cyan couplers, including the compounds disclosed in the two JP-A specifications mentioned above, may not have satisfactory color forming properties, or they may have to be used in large coated weights in order to provide the density which is required because they have a low molecular extinction coefficient. Moreover, these conventional couplers have problems in that the storage properties of the manufactured light-sensitive material prior to color development processing are poor and the colored picture is susceptible to considerable fading. These problems are obstacles to the use of these conventional couplers and they cannot be said to have reached a practical stage at the present time.
On the other hand, acylacetamide couplers and malondianilide couplers are generally used as yellow dye forming couplers (referred to hereinafter as yellow couplers) for forming the yellow image.
The yellow dyes obtained from these couplers are generally formed in a silver halide emulsion layer which is color sensitive to radiation which has a complementary color relationship to the radiation which is adsorbed by the dye, or in a layer adjacent thereto.
Moreover, acylacetamide couplers as typified by the benzoylacetanilide couplers and pivaloylacetanilide couplers are generally used as yellow couplers, and especially for image forming purposes. The former generally have a high coupling activity with the oxidized product of a color developing agent during development and, since the molecular absorption coefficients of the yellow dyes which are produced are high, they are used in the main in color light-sensitive materials for photographing, and especially in color negative films, where a high photographic speed is required. The latter are such that the spectral absorption characteristics and fastness of the yellow dyes are excellent and so in the main they are used in color papers and color reversal films.
However, although the coupling reactivity with the oxidized product of a primary aromatic amine developing agent during color development is high and the molecular extinction coefficient of the yellow azomethine dye which is formed is high with a benzoylacetanilide coupler, there is a disadvantage in that the spectral absorption characteristics of the yellow image are poor. Although the spectral characteristics of the yellow image are excellent with a pivaloylacetanilide coupler, the coupling reactivity with the oxidized product of a primary aromatic amine developing agent during development is low and there is a further disadvantage here in that the molecular extinction coefficient of the yellow azomethine dye which is formed is small.
A high coupling reactivity of a coupler and a large molecular extinction coefficient of the dye which is formed enables high photographic speeds, high gamma values and high color densities to be obtained, and provides so-called high color forming properties. Furthermore, excellent spectral absorption characteristics for the yellow image means that there is a good cut-off on the long wavelength side of the spectral absorption, for example, and that the absorption characteristics have little unwanted absorption in the green region.
Hence, the couplers which provide both advantages, which is to say which provide high color forming properties (high coupler coupling reactivity, large dye molecular extinction coefficient and high yellow dye fastness) and colored images which have excellent spectral absorption characteristics would be very desirable.
As acyl groups for acylacetanilide couplers, the pivaloyl group, the 7,7-dimethylnorbornane-1-carbonyl group and the 1-methylcyclohexane-1-carbonyl group for example have been suggested in U.S. Pat. No. 3,265,506 (U.S. Pat. Re No. 27,848) and the cyclopropane-1-carbonyl group and the cyclohexane-1-carbonyl group, for example, have been suggested in JP-A-47-26133. However, these couplers sometimes have a poor coupling reactivity and consequently the variation in photographic properties due to processing fluctuations during color development processing are sometimes considerable. In addition, the molecular extinction coefficient of the dye is sometimes small or there are problems with poor spectral absorption characteristics of the colored image and with the fastness of the colored image.
Moreover, with the benzoylacetanilide couplers and pivaloylacetanilide couplers which are typical acylacetanilide couplers, couplers which have oil soluble ballast groups within the molecule are mixed with and dissolved in a high boiling point organic solvent and finely dispersed to form a dispersion which is mixed with silver halide to prepare a color light-sensitive material. When this is done there is a disadvantage in that the photographic speed and the color density are reduced when the amount of high boiling point organic solvent added per unit weight of coupler is reduced.